Frequency-indicator.



ETS, .'SSEGNOR T0 GENERAL ELECTRIC l and .in pars Jv ind ,aber i ,nro fue .i windu and sealer, ziie 'iii-equo iiiiia eiiaraeier, il; hai l irdicaiions are iiliey ie resul of foraine in die inni,

di iargely from ine circuits of tlieee wir riese abnormal freouenf.:

i. niiidings arA 'far out oi' tile ciirren'fion'N in the ci i ezmdiifmsj die orque of "y mailu This is pareici die rerjfuencgf drops wel?. minimum frequency niark :l on

scale, and igl'iue below *die ,MQ/J nl Heil ilay cileliluu L runiivit windings are tuned,

Y' iur down or siarieil u i of rire Winding; circ| ne; nliicli condition7 tog'cizlier 'Wi 'nier'erence in the "fwo circuits free, ,xrings ille indiealor5 actuated by the merakie elf-einem,` a ain on the scale? ilrcr l; f' elly.

t. y invention ie' lo overcome ue and cil'ecive manner l 'we u lie iii .i

e recificaiien of Let'sers Eaten-,

Patented Get. 12,

Serial No. "$38,246.

increase :'Jlie torque o1" its respective Winding ain predcierinined frequencies. The y circuits contain devices for ren io a iii/iiniinuni the HOW of mureni in circoli a'ifrequencies within the range f ille insrrinnent, iii? abnormal frequencies, lionere", iliese devices permit a sufficient den* i A "reni. in ilic auxiliary circuits to dei-ei rene in *die high or low ireirinding, according aS the abnormal er is iii or ion', so as to hold the .r oli" 'die scale. In general the a .r;iljf circuits will contain resistance, inducnce and capacity, although under ce1l i', ons ii; not necessary that the auxilf rcuits cont-ain all three of these de- 'aeife it, is ordinarily only necessary id/ against indications ai; Very yuenciee7 and to his end l preferably an auxiliar:r circuit'J containing re- 'nducanee and capacity in paraliel 'inc tuning devices of the Winding which caueeu die indicator to more toward i: u of the instrument scale. This circui; is so adjusted that it producceA an extra torque which assists the downpuliinej niain circuitl 'izo hold the pointer oi lie ier edr` a second auxiliary circiiiit properly` adjusted anioun o3 inducrince and capacity is proaliel with the circuit of Lire- 1 causes the movable member zo ile higher part of the scale. urtlier modi 'icaiions of' my 'invent-ion n be described in greater detail hereafter.

The norel :features which I believe to be cliaracioriz/,ed by' my invention will be definiely indicaied in the claims appended hereto. The features of construction and inode of ogeration will be understood by reference lo the fellmving description taken in rifinaection with 'the accompanying' draw- VVi 'iii li siiov the preferred embodiments or my invention and in Whichf ligure l shows diaframmatically a -iir c nancy indicator embodying the novel 'leaci" :nv invention, and Fig, 2 shows a modified iai-in of such feazures.

' iflie indicator consists of two coils 5-5,

forming a e'iiatienary winding or stationary' element. The movable, elements consist of two coils 6 and 7 positioned at an angle to one another. These coils are pivotally mounted and carry a needle or indicator 8 ,5 which coperates with a scale 9. The Windings of the movable element are connected in parallel with each other and in series with the stationary element. Included in the parallel circuit of each winding are devices for 10 tuning the circuits to a given frequency. These' devices arerepresented by reactances 10 and 11, condensers 12 and 13, and resistances 14 and 15. The relative amount of reaetance, capacity and resistance in the par- 15 allel circuits is preferably adjustable, as is indicated diagrammatically by the adjustable contacts in connection with the reactances and resistances. By means of these devices, the circuits of windings 6 and 7 are 2e tuned for different frequencies, the circuit of winding 6 being tuned for a higher frequency than that of Winding 7. The windings 6 and 7 are placed at an angle to each other and connected so as tu exert opposing forces on the stationary coils 5 5.

In parallel with the tuning` devices of the lower fre nene vindinff 7 are )laced an' adjustable resistance 16, an adjustable reactance 17 and a condenser 18, arranged in seso ries. These latter devices are tuned for a frequency iai: below that for 'which devices 11, 13, and 15 are tuned. Under these conditions, the torque tending to turn the movable element toward the lower end of the 36 scalewill be accentuated at the lower frequency for which the devices 16, 17 and 18 are tuned, and thus there will be no tendency ior the pointer to move back on the scale at frequencies far below that .for -which 40 the circuit of winding 7 is normally tuned. ln parallel with the tuning devices of the higher 'frequency winding 6, are placed the adjutable resistance 19, the adjustable reactance :'20 and the capacity 21. and the eircuit of this auxiliary winding is tuned for a frequency considerably higher than that for Iwhich the main circuit, containing,r the de vices 10, 12 and 14, is tuned. i T he auxiliary circuit 16, 17 and 18 is put in resonanceV at some frequency between zero vand the lowest division on the scale oi' the instrument, and the auxiliary circuit, 19, 20 and 9.1 is put in resonance at some frequency considerably above the highest division on 615 the scale of the instrument.- lVhen the frequency drops to an abnormally low value, the circuit 16, 17 and 18 will approach resonance and will therefore take a greater eurrcnt, thus producing in the winding' 7 a 6o torque suliicient to keep the pointer 8 oil the scale. When the frequency is abnormally high, the auxiliary circuit 19, 20 and 21 performs a similar function.

The tuning ot the auxiliary cil cuits e5 should not be sharp, but should be gradual so that these circuits will take a considera current over fairly wide range of quency. When the tuning is sharp the auxiliary circuits have little eil'ect except at particular frequencies, and the results atn tained are more or less uncertain. To pro` duce this gradual tuning, the inductanecs are provided with iron cores having a considerable iysteresis loss and are' worked at a very high density.

It is probable that the interaction ot all -four circuits of the instrument is responsible for the final result, as it is necessary to have the proper phase on the auxiliary cir-A cuits, since otherwise these circuits will further increase the tendency of the pointer to indicate incorrectly instead ci working properly. The phase relation oi the curN rents in the circuits can be restricted by the adjustable resistances, and it has been 'tonno that these devices are very necessary and important for this purpose.

It is evident that the auxiliary devices 1S), 2G and 21 may be omitted, where very high frequencies are not likely to be encountered. This is usually the condition in practice, since it is only the abnormally low frequencies that are ordinarily encountered. ln Fig. 2, l have shown a slight inodifica tion, in which the desired results are obtained by inserting a relatively large rencance in parallel with the tuning` devices ci the circuit of winding 7, and a relatively small condenser 23in parallel with the tuningl devices of the circuit of winding (l. At lower frequencies, the reactauce will talle more current than at higher frequencies, and accordingly at lower frequencies, the torque of winding,- 7 will be suilicient to .keep the pointer 8 oli the scale. `Vl'lhile, on the other hand, at very high frequencies, the com denser will cause the winding 6 to carry a greater current, and will thus increase its torque, thereby holding` the pointer El oit1 the scale. ln this manner, :false indications at frequencies far above or far below that for which the instrument is designed will. be avoided. This device is, however, not as satisfactory under all conditions as that shown in Fig. 1, since at certain particular frequencies it tails to accomplish the desirial results. y

l do not desire to limit .myself to the particular construction and arrangement ot parts shown and described, but aim in the appended claims, t'o cover all modifications which are within the scope ol my invention.

That I claim as new and desire te secure by Letters Patent oi' theUnited States, is

1. A frequency indicator compris ig reizt tively movable elements, one oi said elements having two windings exerting oppos. ingF forces on the other element, means for tuningr the circuit of' each of said windings :tor different frequencies, means :for acccntuating the torque of one of said windings at frequencies differing considerably from the frequency for which -the circuit of said winding` is tuned, and indicating means actuated by the movable element.

2. A frequency indicator comprising relatively ymovable elements, one of said' elements having two windings exerting opposing forces on the other element, means for timing the circuit of one of said wind'- ings for one frequency, means for timing the circuit of the other winding for a lower frequency, means for accentuat-ing the torque exerted vby said last mentioned winding at frequencies lower than that for which the circuit of said winding is timed, and indicating means actuated by the movable element.

3. A frequency indicator comprising relatively movable elements, one of said elements having two windings exerting opposing` forces on the other element. means for timing the circuit of one of said windings for relatively high frequencies, means for tuning the circuit of the other winding for relatively low frequencies, means for accentuating the torque exerted by said first winding at frequencies far higher than that for* which tliecircuit-of said winding is tuned, means for accentuatingthc torque exerted by said second winding at frequencies far lower than thatfor which the circuit of said winding is timed, and indicating means actuated by the movable element.

4. A frequency indicator comprising relatively movable elements, one of said cle ments having two windings exerting opposing forces on the other element, means for tuning the circuit of each of said windings for different frequencies, auxiliary means for tuning the circuit of one of said wiiid ings for a still ditl'crent frequency, and indicating means actuated by the movable element.

5. A frequency indicator comprising rela tively movable elements, one of said elements having two windings exerting opposin'g forceson the other element, means foi' tuning the, circuit of one of said windings for one frequency, means for timing the circuit of the`other winding for a. lower frequency` an inductance in parallel with said last mentioned means, and indicating means actuated by the movable element.

G. A frequency indicator comprising relativelymovable elements, one of said ele ments having two windings exerting opposi ing forces on the other element, means for timing the circuits of the two windings for two different frequencies, said 'two frequencies being relatively above and below the average frequency to be measured, means l' for accentuatn'ig the torque of the winding ments having two windings exerting opposing forces on the other element, a device in series with each winding for adjusting the impedance of the circuits of said windings,

additional devices in parallel to one of said first mentioned devices for furtheradjusting the impedance of the circuit of one of said windings, and indicating means actuated by the movable elements.

S. A frequency indicator comprising relatively movable elements, one of said elements having two windings exerting opp0sing forces on the other element, a reactance and a condenser in series with each of said windings, a reactance and a condenser in parallel. with the reactance and condenser of one of said windings, and indicating means actuated by the movable element.

9. A frequency indicator comprising relatively movable elements, one of said ele,- inents having two windings exerting opposin'g forces on the other element, a reactance and a condenser in series with each of said windings, a resistance, a reactance and a condenser in ,parallel with the reactance and condenser of one of said windings, and indicating means actuated by the movable element.

10. A frequency indicator comprisingrelatively movable elements, one of said ele ments having two windings exerting oppos ing forces on the other element, means for tuning the circuit of each of said windings for different' frequencies, `a reactance in parallel with the tuning devices of one of said circuits, said reactance having a large hysteresis loss, and indicating means actuated by the movable element.

ln witness whereof, I have hereunto set my hand this 10th day ot' July, 1912. DAVID R. PRICE. Witnesses JA Mns H. CA tiranni., LAURA MeLAnnN. 

